Line-type grass cutting head which can be alternatively used on machines with left or right rotation

Abstract

The head comprises a housing ( 3 a, 3 B) for a winding spool ( 7 ) for winding the cutting line (F), provided with projections ( 15, 19 ) cooperating with teeth ( 17, 21 ) integral with the housing. The teeth and the projections are arranged in such a way so as to allow a stepped rotation of the spool with respect to the housing, when said spool is translated alternatively in opposite directions parallel to the axis of the head. The head comprises a first series of teeth and a second series of teeth ( 21 A, 21 B) which can be used alternatively and which are suitable each to allow the rotation of the spool ( 7 ) in one direction and to prevent the rotation in the opposite direction with respect to the housing.

1. A line-type grass cutting head, comprising:
 a spool for winding a cutting line, said spool comprising a first set of projections and a second set of projections; 
 a housing comprising a first housing portion and a second housing portion, said first housing portion comprising a first plurality of teeth, said first set of projections cooperating with said first series of teeth, said housing defining an inner volume, said inner volume receiving said spool, said second housing portion comprising a first side surface and a second side surface, said first side surface being opposite said second side surface, said first side surface defining a plurality of second teeth, said second side surface defining a plurality of third teeth, one of said plurality of second teeth and said plurality of third teeth being located at a position outside of said inner volume, another of said plurality of second teeth and said plurality of third teeth being located at a position in said inner volume; 
 an elastic member elastically loading the spool with respect to the housing. 
 
     
     
       2. A line-type grass cutting head in accordance with  claim 1 , wherein said plurality of second teeth are symmetrical to said plurality of third teeth. 
     
     
       3. A line-type grass cutting head in accordance with  claim 2 , wherein each of said plurality of second teeth comprises a second tooth inclined surface portion, a second tooth abutment surface portion and a second tooth planar surface portion, said second tooth abutment surface portion being substantially parallel to a rotational axis of said spool, said second tooth planar surface portion being substantially perpendicular to said rotational axis of said spool, each of said plurality of third teeth comprising a third tooth inclined surface portion, a third tooth abutment surface portion and a third tooth planar surface portion, said third tooth abutment surface portion being substantially parallel to said rotational axis of said spool, said third tooth planar surface portion being substantially perpendicular to said rotational axis of said spool, said second tooth inclined surface portion of each of said plurality of second teeth having a height that increases in a first circumferential direction of said second housing portion, said third tooth inclined surface portion of each of said plurality of third teeth having a height that increases in a second circumferential direction of said second housing portion, said first circumferential direction being opposite said second circumferential direction. 
     
     
       4. A line-type grass cutting head in accordance with  claim 3 , wherein said second housing portion is connected to said first housing portion with said second housing portion being in a first position, at least a portion of said plurality of second teeth being located in said inner volume with said second housing portion in said first position, said plurality of third teeth being located at a position outside of said housing with said second housing portion in said first position, said plurality of second teeth cooperating with said second set of projections with said second housing portion in said first position such that said spool is rotatable in said first circumferential direction with respect to said housing and said spool is non-rotatable in said second circumferential direction with respect to said housing, at least a portion of said plurality of third teeth being arranged in said inner volume with said second housing portion in said second position, said plurality of second teeth being located at a position outside of said housing with said second housing portion in said second position, said plurality of third teeth cooperating with said second set of projections with said second housing portion in said first position such that said spool is rotatable in said second circumferential direction with respect to said housing and said spool is non-rotatable in said first circumferential direction with respect to said housing, wherein said first set of projections, said second set of projections, said first series of teeth and one of said second series of teeth and said third series of teeth are arranged such as to allow a stepped rotation of the spool with respect to the housing when said spool is translated alternatively in opposite axial directions parallel to the axis of the head. 
     
     
       5. A grass-cutting head in accordance with  claim 4 , wherein:
 said plurality of second teeth and said plurality of third teeth have the same orientation when viewed in cross section. 
 
     
     
       6. A grass-cutting head in accordance with  claim 4 , wherein one of said first housing portion and said second housing portion comprises at least one bushing for receiving at least a portion of the cutting line. 
     
     
       7. A grass-cutting head as claimed in  claim 4 , wherein said second housing portion of has a central aperture, said spool comprising a knob, said knob extending through said central aperture, said knob forming a member for controlling the stepped rotation of the spool and correspondingly elongation of the cutting line during the rotation of the head. 
     
     
       8. A line-type grass cutting head, comprising:
 a housing comprising a first housing portion and a second housing portion, said housing defining an inner volume for a take-up spool for winding a cutting line, said take-up spool being provided with a first set of projections cooperating with a first series of teeth integral with one of said first housing portion and said second housing portion, wherein the other of said first housing portion and said second housing portion is provided with a second series of teeth and a third series of teeth arranged on opposite sides thereof, wherein said other of said first housing portion and said second housing portion being connectable to said one of said first housing portion and said second housing portion in two positions such that said second series of teeth is located inside said housing in one of said two positions and said third series of teeth is located inside said housing in another of said two positions, wherein said second series of teeth allow rotation of said take-up spool with respect to said housing in one direction and said second series of teeth prevent rotation of said take-up spool with respect to said housing in an opposite direction when said second series of teeth is inside said housing, said third series of teeth preventing rotation of said take-up spool with respect to said housing in said one direction and allowing rotation of said take-up spool in said opposite direction when said third series of teeth is inside said housing, said take-up spool being provided with a second set of projections cooperating with one of said second series of teeth and said third series of teeth, wherein said first set of projections, said second set of projections, said first series of teeth and said one of said second series of teeth and said third series of teeth arranged inside said housing are arranged such as to allow a stepped rotation of the spool with respect to the housing when said spool is translated alternatively in opposite axial directions parallel to the axis of the head; 
 an elastic member elastically loading the spool with respect to the housing. 
 
     
     
       9. A grass-cutting head as claimed in  claim 8 , wherein:
 each of said second series of teeth and said third series of teeth has a profile with inclined surfaces and abutment surfaces cooperating with corresponding projections of said second set of projections of said take-up spool; and 
 said second series of teeth and said third series of teeth have the same orientation when viewed in cross section. 
 
     
     
       10. A grass-cutting head as claimed in  claim 9 , wherein one of said first housing portion and said second housing portion comprises at least one bushing for passage of the cutting line. 
     
     
       11. A grass-cutting head as claimed in  claim 8 , wherein one of said first housing portion and said second housing portion comprises at least one bushing for passage of the cutting line. 
     
     
       12. A grass-cutting head as claimed in  claim 11 , wherein said one of said first housing portion and said second housing portion, on which the second series of teeth and the third series of teeth are provided, has a central aperture, through which a knob projects, said knob being integrally connected to said spool, said knob forming a member for controlling the stepped rotation of the take-up spool and correspondingly elongation of the cutting line during the rotation of the head. 
     
     
       13. A grass-cutting head as claimed in  claim 8 , wherein said first housing portion includes at least a bushing for the passage of the cutting line and said second housing portion forms a closing member for said first housing portion. 
     
     
       14. A line-type grass cutting head, comprising:
 a spool for winding a cutting line, said spool comprising a first set of projections and a second set of projections; 
 a housing comprising a first housing portion and a second housing portion, said first housing portion comprising a first plurality of teeth, said housing defining an inner volume, said spool being arranged in said inner volume, said first set of projections cooperating with said first series of teeth, said second housing portion comprising a second series of teeth and a third series of teeth, said second series of teeth being arranged on a first side of said second housing portion, said third series of teeth being arranged on a second side of said second housing portion, said first side being opposite said second side, said second housing portion being connected to said first housing portion with said second housing portion being in a first position, at least a portion of said second series of teeth being located in said inner volume with said second housing portion in said first position, said third series of teeth being located at a position outside of said housing with said second housing portion in said first position, said second series of teeth cooperating with said second set of projections with said second housing portion in said first position such that said spool is rotatable in a first direction with respect to said housing and said spool is non-rotatable in a second direction with respect to said housing, said first direction being opposite said second direction, at least a portion of said third series of teeth being arranged in said inner volume with said second housing portion in said second position, said second series of teeth being located at a position outside of said housing with said second housing portion in said second position, said third series of teeth cooperating with said second set of projections with said second housing portion in said second position such that said spool is rotatable in said second direction with respect to said housing and said spool is non-rotatable in said first direction with respect to said housing; 
 an elastic member elastically loading the spool with respect to the housing. 
 
     
     
       15. A line-type grass cutting head in accordance with  claim 14 , wherein said first set of projections, said second set of projections, said first series of teeth and one of said second series of teeth and said third series of teeth are arranged such as to allow a stepped rotation of the spool with respect to the housing when said spool is translated alternatively in opposite axial directions parallel to the axis of the head. 
     
     
       16. A grass-cutting head as claimed in  claim 15 , wherein said second housing portion of has a central aperture, said spool comprising a knob, said knob extending through said central aperture, said knob forming a member for controlling the stepped rotation of the spool and correspondingly elongation of the cutting line during the rotation of the head. 
     
     
       17. A grass-cutting head in accordance with  claim 14 , wherein:
 each of said second series of teeth and said third series of teeth has a profile with inclined surfaces and abutment surfaces cooperating with corresponding projections of said second set of projections of said spool; and 
 said second series of teeth and said third series of teeth have the same orientation when viewed in cross section. 
 
     
     
       18. A grass-cutting head in accordance with  claim 17 , wherein one of said first housing portion and said second housing portion comprises at least one bushing for receiving at least a portion of the cutting line. 
     
     
       19. A grass-cutting head in accordance with  claim 14 , wherein one of said first housing portion and said second housing portion comprises at least one bushing for receiving at least a portion of the cutting line. 
     
     
       20. A grass-cutting head in accordance with  claim 14 , wherein said first housing portion includes at least a bushing for receiving at least a portion of the cutting line and said second housing portion forms a closing member for said first housing portion.